The present invention relates to a drink extraction apparatus for extracting drink such as coffee and black tea.
In a conventional drink extraction apparatus, the extract liquid extracted by pouring hot water over the powered coffee or black tea leaves placed in a bucket is stored in a drink container made of glass called decanter and kept warm therein. A typical method for keeping a drink container warm include a method for placing the drink container on a heat retention plate equipped with a heater.
In the keep-warm method with use of the heat retention plate, heat from the heater is directly conducted to extract liquid inside the decanter, which overheats the extract liquid and causes such problems as overboil of the extract liquid, thereby damaging flavor of the drink. In addition, the method has a defect that insufficient contact between the bottom surface of the decanter and the heat retention plate changes the correlation between the temperature of the heat retention plate and the temperature of the extract liquid inside the decanter, which disturbs keeping the drink warm at a specified temperature.
Japanese Utility Model Laid-Open Publication HEI No. 5-70422 has proposed a method for surrounding a decanter placed on a heat retention plate with a transparent heat retention cover together with a bucket to reduce power consumption of a heater. Although this method is capable of preventing heat discharge with the heat retention cover, the defect of the method with use of the heat retention plate is not at all corrected due to the very presence of the heat retention plate. Further, the heat retention cover requires detachment every time the decanter needs to be put in and out, which makes operation extremely intricate.
Japanese Patent Laid-Open Publication HEI No. 8-38363 has proposed a method for placing a decanter on a heat retention plate via a heat retention case to form a space layer between the heat retention plate and the bottom surface and outer lateral side of the decanter, for decreasing heat discharge from the decanter and reducing power consumption of a heater, as well as for providing uniform heat retention of the decanter via the space layer. This method, however, has a defect that the size of a main body of the apparatus is increased by the space layer provided between the heat retention plate and the decanter.
Further, Japanese Patent Laid-Open Publication HEI No. 10-146277 has proposed a method in which a coffee server is composed of a coffee receiver tank and a heat retention tank for surrounding the coffee receiver tank from outside, and hot-retained water is pouring in between the coffee receiver tank and the heat retention tank to heat the coffee in the coffee receiver tank with hot water and keep it warm. The method with hot water has defects that a water heating mechanism is required and the coffee server itself becomes larger and heavier.
A conventional drink extraction apparatus such as coffee makers has a feedwater tank having an upper opening for receiving water. The received water is fed from the feedwater tank to a water boiler tank, where the water is heated and delivered through a delivery pipe to the powdered coffee contained in a bucket, so that coffee liquid is extracted from the powdered coffee and is supplied to a drink container. A water receiving cover having a perforated portion is fastened to the opening of the feedwater tank with a screw for preventing dirt and the like contained in water from traveling the feedwater tank and reaching the water boiler tank. A cover plate of the water boiler tank is provided with a steam pipe disposed so as to protrude inside the feedwater tank for discharging water vapor generated in the water boiler tank.
However in the conventional drink extraction apparatus, the water receiving cover is fastened so that maintenance operation of the feedwater tank such as cleaning is not available, and therefore the feedwater tank tends to be unclean. In addition, a large amount of water vapor is discharged to outside through the steam pipe, which indicates that hot water inside the water boiler tank naturally evaporates and an amount thereof decreases, causing a problem that extraction of a specified amount of coffee liquid is not available.
It is an object of the present invention to provide a drink extraction apparatus capable of keeping extract liquid warm at a proper temperature without deteriorating the extract liquid during keeping it warm. It is another object of the present invention to provide a small-size drink extraction apparatus. It is still another object of the present invention to provide a drink extraction apparatus capable of controlling the temperature of extract liquid with safety.
It is a further object of the present invention to provide a drink extraction apparatus having a container housing case for facilitating insertion and extraction of a container with a grip.
It is a still further object of the present invention to provide a drink extraction apparatus for facilitating maintenance operation of a feedwater tank and for performing dew condensation of water vapor and returning the dew to a water boiler tank to reduce escape of water vapor.
In order to accomplish the above objects, the present invention provides a drink extraction apparatus comprising:
a drink extraction portion;
a drink container for storing drink extracted by the drink extraction portion;
a heat retention chamber surrounding the drink container;
a fan for supplying air to the heat retention chamber for air circulation; and
a heater for heating air supplied to the heat retention chamber by the fan to make warm air,
the warm air heating the drink container to keep drink therein warm.
In the drink extraction apparatus of the present invention as structured above, air sent by the fan is heated by the heater and supplied to the heat retention chamber, where air flows around the drink container to uniformly heat the drink container, and then returns to the fan and circulates. Thus, extract liquid in the drink container is kept warm at a proper temperature.
The heat retention chamber is preferably composed of a lateral wall surrounding the peripheral surface of the drink container, a bottom wall for receiving the bottom surface of the drink container, and an upper wall having an opening portion for covering the upper side of the drink container and falling extracted drink from the bucket to the drink container. Such structure makes it possible to prevent escape of heat wave as well as to uniformly heat the drink container from the periphery thereof.
On the lateral wall, there are preferably formed an air outlet for blowing out air sent from the fan toward the heat retention chamber, and an air inlet for sucking air in the heat retention chamber and returning the air to the fan. In such structure, air blown from the air outlet to inside of the heat retention chamber flows along the peripheral surface of the drink container through a space between the lateral wall and the drink container and flows out to the air inlet, thereby enabling smooth air circulation.
Part of air blown out from the air outlet is preferably directed toward the lower side of the drink container. This enables heat retention at a proper temperature even when the amount of extract liquid in the drink container is small.
Part of the lateral wall is preferably made of a door for putting the drink container in and out. The door may be a pair of right and left biparting doors. In the case of using the biparting doors, an opening portion for exposing a grip of the drink container outside is preferably formed in a joint portion of a pair of the right and left doors. This makes it easy to putting the drink container out of the heat retention chamber.
At least the lateral wall of the heat retention chamber preferably has a heat insulation structure. Here, the heat insulation structure may be an air layer. This enables control of heat discharge from the lateral wall. Further, structuring the lateral wall with a transparent material makes it possible to check the amount of drink in the drink container.
It is preferable to further provide a temperature sensor for detecting the temperature of air supplied to the heat retention chamber and a control unit for turning on and off the heater based on the temperature detected by the temperature sensor to control the temperature of air in the heat retention chamber. Here, the temperature sensor is preferably attached to a radiation fin provided on the heater or in the vicinity of the radiation fin. This enables the temperature sensor to detect abnormal heat generation of the radiation fin in the case of the fan failure and to turn off the heater, thereby securing safety.
Preferably, the door is mounted rotatably around a rotation axis, in the vicinity of which an inner door is extensively provided so as to protrude inside a container housing case when the door is closed and to cover the opening portion of the container when the door is opened. A notch is provided on the door for allowing the grip of the container to protrude outside.
According to the container housing case, for putting the container with a grip out of the container housing case, the grip protruding to the outside is held through the notch of the container housing case and dragged. Consequently, the outside surface of the container presses the inside surface of the door, so that the door opens as the container is dragged, which enables extraction of the container. In the state of the container being put out, the opening portion of the container housing case is closed by the inner door. For putting the container with a grip in the container housing case, the grip is held to press the container against the inner wall. Consequently, the door is closed as the container is pressed, which enables insertion of the container in the container housing case.
The inner door may be in the shape of a cylinder or a board. In the case where the inner door is in a cylinder shape, the structure thereof is simple and the weight thereof is small. In the case where the inner door is in a board shape, the plate shaped inner door may block the inside and outside of the container housing case when the door is opened. The container housing case is preferably provided with a double wall made of two plates facing each other with an air layer interposed therebetween. Such structure enables control of heat discharge from the side wall.
On the inner wall of the container housing case, a straightening vane is preferably provided for guiding warm air to flow along the periphery of the container. Such structure implements smooth warm air flow and sufficient heat retention or cold insulation of the container.
The drink extraction portion is preferably composed of a feedwater tank, a water boiler tank having a heater, a feedwater pipe for connecting the water boiler tank and the feedwater tank, a bucket provided above the drink container for accommodating an extract, and a discharge pipe for discharging hot water from the water boiler tank into the bucket. The heat retention chamber is preferably provided under the bucket, and the fan and the heater are preferably provided behind the heat retention chamber and under the water boiler tank. Such configuration enables effective use of space under the water boiler tank and removal of a heat retention plate and a heater portion under the drink container to decrease the overall height of the apparatus, resulting in downsizing.
It is preferable that the drink extraction portion is further composed of a steam pipe extending to the upper side from the water boiler tank and protruding inside the feedwater tank, the feedwater tank has an opening opened upwardly for receiving water, a water receiving cover having a perforated portion for allowing received water to pass therethrough is mounted in a demountable way on the feedwater tank so as to cover the opening of the feedwater tank, and the water receiving cover is provided with a small chamber opened downwardly for covering the upper side of the steam pipe. Such structure makes it possible to demount the water receiving cover to perform maintenance operation of the feedwater tank such as cleaning. Water vapor generated in the water boiler tank travels through the stem pipe and reaches the small chamber of the water receiving cover, where dew condensation occurs and resultant dew flows down into the feedwater tank and returns to the water boiler tank.
Above the perforated portion of the water receiving cover, a filter for filtering received water is disposed. This enables removal of small dirt, dust, bleaching powder, and the like contained in water received in the water boiler tank.
A recessed portion is provided on the water receiving cover to form the perforated portion on the bottom of the recessed portion. This makes it possible to prevent water received in the feedwater tank from splashing.
On the peripheral verge of the water receiving cover, there is provided a leg portion extending downside, the lower end of which is brought into contact with the bottom of the feedwater tank. This facilitates mounting of the water receiving cover.
On the outer surface of the leg portion of the water receiving cover, an engagement groove extending in vertical direction is provided, and a protruding bar for engaging with the engagement groove is provided in a protruding way on the lateral wall of the feedwater tank. This makes it possible to prevent the water receiving cover from moving in horizontal direction. The engagement groove is preferably formed to have a width narrowed toward the lower side. An opening verge of the engagement groove is preferably provided with a protruding portion that is tightly fitted into the protruding bar.
An engagement protruding portion is provided on the outer surface of the leg portion of the water receiving cover, and a protrusion for engaging with the engagement protruding portion is provided in a protruding way on the lateral wall of the feedwater tank. This makes it possible to prevent the water receiving cover from moving in vertical direction.